Synthesis and transition metal coordination chemistry of a novel hexadentate bispidine ligand

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 44; no. 6; pp. 2724 - 2736
• Main Authors: Comba, Peter, Rudolf, Henning, Wadepohl, Hubert
• Format: Journal Article
• Language: English
• Published: England 14.02.2015
• Subjects: Azabicyclo Compounds - chemistry; Coordination Complexes - chemical synthesis; Coordination Complexes - chemistry; Crystallography, X-Ray; Models, Molecular; Molecular Structure; Transition Elements - chemistry
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c4dt03262d

Reported is the new bispidine-derived hexadentate ligand (L = 3-(2-methylpyridyl)-7-(bis-2-methylpyridyl)-3,7-diazabicyclo[3.3.1]nonane) with two tertiary amine and four pyridine donor groups. This ligand can form heterodinuclear and mononuclear complexes and, in the mononuclear compounds discussed here, the ligand may coordinate as a pentadentate ligand, with one of the bispyridinemethane-based pyridine groups un- or semi-coordinated, or as a hexadentate ligand, leading to a pentagonal pyramidal coordination geometry or, with an additional monodentate ligand, to a heptacoordinate pentagonal bipyramidal structure. The solution and solid state data presented here indicate that, with the relatively small Cu(II) and high-spin Fe(II) ions the fourth pyridine group is only semi-coordinated for steric reasons and, with the larger high-spin Mn(II) ion genuine heptacoordination is observed but with a relatively large distortion in the pentagonal equatorial plane.